The objective of this research is to learn the detailed mechanism of action of various metal-activated and metallo-enzymes. When an enzyme is activated by or contains a paramagnetic metal ion (Mn, Co, Cu, Fe), or interacts with a paramagnetic substrate analog, structural, kinetic and thermodynamic information can be obtained about the immediate environment of the paramagnetic center by electron spin resonance and by nuclear magnetic resonance studies of the solvent, the substrates and the protein. The most useful NMR parameter is the longitudinal relaxation time (T1) of the nuclei of the substrate since rapid and accurate determinations of T1 permit distance calculations in solution. At least an order of magnitude improvement in the accuracy and speed of T1 determination has been made possible by our use of Fourier transform NMR spectroscopy. Using the Fourier transform method for measuring T1 of protons, phosphorus, carbon and other atoms of substrates and enzymes, the structures of ternary complexes of several metal activated enzymes will be investigated. The enzymes under investigation catalyze the transfer of phosphoryl groups (pyruvate kinas, phosphoglucomutase, and succinyl CoA synthetase), nucleotidyl groups (DNA and RNA polymerase), and CO2 or bicarbonate (transcarboxylase, carbonic anhydrase). Also being studied are enzymes which carry out carbon-carbon bond formation (aldolases) as well as certain hemoproteins (cytochrome b, hemoglobin). The purpose of studying a large number of enzymes is to seek general principles of enzyme chemistry which might be used untimately to control the rate and course of enzyme reactions in vivo and in vitro. Our finding of a unique substrate conformation on DNA polymerase and the presence of Zn in DNA polymerases from four sources might conceivably provide a basis for the design of chemotherapeutic agent for malignant disease. BIBLIOGRAPHIC REFERENCES: Fung, C.H., Gupta, R.K. and MIldvan, A.S. (1975) Abs. 170th Meeting of American Chemical Society, Chicago, Ill. BIOL-43. Fung, C.H., Gupta, R.K. and Mildvan, A.S. (1975) Biochemistry, in press.